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When the torch is moved from side to side, Fig. 7-7, more material is heated to the ignition temperature so that additional material is oxidized and blown out of the kerf.

The eyes must also be protected from the heat coming from the job.

The history of the iron and steel industry in North America extends back over 300 years, beginning with a successful ironworks in Saugus, Massachusetts, about 20 miles northeast of Boston. It operated from 1646 to 1670.

If a fire should occur, properly trained personnel should use dry sand, powdered graphite, or commercially available Metal-X* to extinguish the titanium.

The amount of lag can be expressed as a percentage of the plate thickness, Fig. 7-8.

When the torch is held in a vertical position and the cutting conditions are correct, this line is vertical from top to bottom, Fig. 7-18 (1). This condition is referred to as zero drag.

For cutting plate of 6 inches or heavier, propane, propylene, or Mapp® gas are better choices. Because a deep area must be heated, the dispersed BTU's, the bushy flame, and the high total BTU content of these gases do a good job in heavy plate cutting, Fig. 7-4.

In the oxyacetylene flame, BTU's are created mainly in the inner cone. With the other gases, BTU's are largely dispersed through the outer flame envelope, Fig. 7-3.